RF Energy Harvesting Sensor Tags for Battery-Free IoT
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Solution Overview
Problem
Existing wireless sensor networks face challenges in maintaining power for large-scale deployments, as traditional battery maintenance becomes unfeasible for hundreds of sensors in commercial applications, necessitating an efficient energy harvesting solution.
Innovation Solution
A network sensor system that utilizes RF energy harvesting, converting ambient RF energy into DC power using an energy harvesting unit, storing it, and using Bluetooth Low Energy (BLE) advertising packets to transmit sensor data without the need for battery pairing, enabling continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional batteries are used to power wireless sensors in large-scale deployments, then initial power supply is sufficient, but maintenance becomes unfeasible for hundreds of sensors
Solution Approach 1:
The sensor system performs self-powered operation by harvesting RF energy from the ambient environment to continuously recharge its power storage unit. This self-service mechanism eliminates the need for external battery replacement or recharging, allowing hundreds of sensors to operate autonomously without technician intervention for maintenance.
2Duration of action of stationary object
If RF energy harvesting is used to eliminate battery maintenance, then operational continuity is improved, but energy conversion efficiency becomes critical
Solution Approach 1:
The system merges multiple energy harvesting functions into a single integrated energy harvesting unit that processes RF energy from both dedicated emitters and ambient sources. This combined approach maximizes energy capture efficiency by utilizing all available RF energy sources simultaneously, reducing energy loss and ensuring continuous operation.
Solution Approach 2:
The energy harvesting unit dynamically adjusts its operating parameters to optimize conversion efficiency under varying RF energy conditions. By changing operational parameters based on available energy levels, the system maintains high efficiency across different environmental conditions while ensuring continuous operation.
3Device complexity
If sensor data transmission is implemented without battery pairing, then deployment complexity is reduced, but power management requirements increase
Solution Approach 1:
The sensor tags automatically manage their own power by harvesting RF energy and storing it in local power storage units. This self-service power management eliminates the need for complex pairing procedures with external battery systems, reducing deployment complexity while maintaining full automation of power supply operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system allows for perpetual operation of sensor tags by harnessing ambient RF energy, eliminating the need for battery maintenance and enabling efficient data transmission, thereby addressing the power management challenges in large-scale sensor networks.
Implementation Method 1
an energy harvesting unit operable to convert incident RF energy to direct current (DC) including RF energy from the RF emitter and RF energy from one or more ambient sources
Data Source
AI summary
A network sensor system and method for using the same are disclosed herein. In one embodiment, the network sensor system comprises: a radio-frequency (RF) emitter; a first sensor tag including a transmitter, an energy harvesting unit operable to convert incident RF energy to direct current (DC) including RF energy from the RF emitter and RF energy from one or more ambient sources, a storage unit operable to store recovered DC power, one or more sensors for sensing and logging data, a controller coupled to the energy harvesting and storage units, the one or more sensors and the transmitter, to communicate data in the form of a Bluetooth Low Energy (BLE) advertising packet using energy previously harvested and stored by the energy harvesting and storage unit; and a first device to receive the BLE advertising packet.